2011 census: Methodology
We used a range of statistical methodologies to ensure the 2011 census results were consistent and complete.
The key elements of statistical processing we used were developed by the Office for National Statistics.
Coverage estimate and adjustment
Coverage estimate and adjustment allows us to make an estimate of Scotland’s entire population.
Although we work to ensure the census counts everyone in Scotland, it will always miss some people. This process estimates how much of the population was missed. It identifies and adjusts for people who were:
- counted more than once
- counted in the wrong place
Find out more
The 2011 census Estimation and Adjustment Strategy contains more details on the process.
Release 1C: How the 2011 Census population estimates were obtained summarises the statistical methodology used to estimate the 2011 census population and household estimates.
Scotland’s Census 2011 data quality for coverage records covers the data quality issues that originated from the estimation and adjustment process.
Edit and imputation
Edit and imputation finds and fixes inconsistencies and gaps in census data.
For example, a person might miss a question in the census questionnaire, or enter a parent-child relationship the wrong way around.
Edit and imputation finds and fills gaps to create a consistent and complete dataset.
Statistical disclosure control
There is a risk that individual people can be identified in census results.
For example, everyone in an area may be aged under 50 except a single old-age pensioner. A search of the area by age and general health could reveal information about that pensioner’s health.
We use statistical disclosure control and table design to prevent individuals and their information from being identified in census results.
Statistical disclosure control is applied in the same way across all UK censuses. Find out more on the Office for National Statistics website.
Census results can be searched by a range of area types, or geographies.
Census output areas, which average around 50 households in size, are the smallest geographies. They form the building blocks for larger geographies.
See a complete list of geographies for the 2011 census.
Find out more
Find out more about census geographies in:
- points 5 to 8 of the Spring 2010 Consultation on Statistical Outputs: Analysis of Responses
- section 4 of the February 2011 Census Outputs Consultation
Find further information about geographies on the ONS website.
2011 census methodology publications
We published outputs from the 2011 census in a series of releases. Alongside these releases, we also published information about the methodology we used.
These publications were:
- Release 1A
- Release 1B
- Release 1C: How the Census Population Estimates were obtained
- Components of the alternative household estimate in the CCS sample by Processing Units, Hard to Count group and type
- Confidence intervals of population estimates, by age group and gender
- Variables collapsed and reason for collapsing key estimation variables by Processing Unit
- Census Coverage Survey, household response rate and sample size by Local Authority
- 2011 Census: 95% confidence interval widths by age group and sex, Scotland
- 2011 Census: 95% confidence interval widths, by council area
- Census: percentage person response rate, by council area